Obviously, the problems run deeper than just boiling it down to Garret must go. However, and maybe I'm naive about this, I feel getting the right head coach in here fixes a lot of the problems.
Have we done a poor job of fixing our defense over the years? Absolutely. Ultimately, that's a GM problem but it's also a problem with the coach's priorities. Look at how fast Parcells switched us over from a 4-3 into a 3-4. He was far from perfect, but Parcells came in with a goals that he accomplished quickly to get us back into the playoffs. His main failing was not finding the QB who could lead that team to success, but he had him on the roster. Instead, Parcells was behind bringing in Bledsoe and Testaverde. Those decisions didn't work out, but they were his decisions.
Now, we want to say that Garrett is at the mercy of the Joneses. I don't believe that's the case. I believe a head coach here can have just as much of a say as Parcells had if he's willing to stand up for what he believes he needs to win. As Parcells said, he might have to convince Jerry, but Jones can be convinced.
If we blame the Joneses for every personnel move that doesn't work, for not stocking the defense, etc., then we're letting Garrett off the hook. Truth is that they are all to blame because they work as a team in making the decisions they've made. The Joneses aren't going to leave the team, though, so the best we can hope is that they recognize that Garrett isn't the answer and find a stronger teammate who can carry them, like Johnson did and Parcells was attempting to do before he burned out.